Muller



Dec. 24, 1929. v I 1.. a. COPES MULLER Filed Oct, 20, 1926 INV NTORPatented Dec. 24, 1929 IJtAdZ p in LOUIS GEGRGE COTPES,

OF BAYONNE, NEW JERSEY MULLER In such 0 )erations as the rubbin or rind-1 b 2: mg of pigments with oil or other vehicle by means of tl 1econventional form of muller or uniformity particles regardless of theseverance of the operator.

of subdivision of the pigmen industry and per- By one or the other ofthese well known and universally used methods it is practically1mposs1ble even after protr or spatula,

acted manipulation of the muller to produce a mixture in which someparticles of pigment have not escaped completely the grinding action ofthe appliance, or at least in which part of the pigment is much lesmainder.

s thoroughly ground than the re- The invention relates to an improvedform of muller which is apphcable to the grinding of pi ments or s1milarpulverulent materials with oil or other vehicle, simulating in principleand effect the action of the conventional paint mill upon mixtures ofthe type used in manufacturing paints, and when properly manipulatedyielding a product of wh1ch none of the a solid portion (pigment) canescape the desired thorough and uniform grinding action of theappliance, and this too in a relatively brief time and with a minimum oflabor.

One convenient form of the invention is illustrated wherein Figure 1 inthe accompanying drawings,

is an inverted or bottom plan view of a muller embodying my invention.

Figure 2 is a vertical sectional view thereof.

the muller surface.

upon material lodging on a plane The muller consists essentially of ahollow, tubular unit, preferably cylindrical, of steel,

glass, porc elain, or other suitable material,

of a size convenient to fit the hand. The

under surf grinding surface. I

be a smooth plane surface, as at A, Figmay ure 1, but may be, an

ace of the muller constitutes the Such grinding surface preferably thegrinding surface d is, indented at B, such indentations being in theform of channels arranged in comparatively close order as shown in theupper left-hand portion of Figure 1. These channels are shown astangential to the cylindrical surfaces of the muller. Said channels havetheir origin at the point at which the beveled edge B, Figure 2, formsan angle with the grinding surface, (this angle is indicated at C,Figure 2,) and extending almost to the outer edge of the grindingsurface, (E, Figure 1.) in that type where the channels are present, thenon-channeled portion of the grinding surface is an unbroken planecircle surrounding the channeled area, and which may be approximatelyinch in width. The purpose of these channels is to aid the grindingsurface in taking the mixture to be ground, thus hastening the action ofthe appliance. A further aid in feeding the unground material to thegrinding surface is provided by having the interior lower edge of theappliance beveled at a suitable angle, this bevel being shown at E,Figure 2. To prevent the discharged, ground product from reentering themuller, the outer right angle formed by the junction of the bottomgrinding surface with the exterior wall is made a sharp edge, D, Figure2.

The muller is used in conjunction with any smooth or matt surface, hardplaten or grinding plane, in similar manner to the use of an ordinarymuller or spatula.

My invention is a hand operated unit as distinguished from a poweroperated grinder, and in service my muller is grasped in the hand, andpressure is applied directly to the muller and it is moved in a circularor oscillatory path, in a manner to press and move the lower channeledsurface upon the material present between the platen and the lowerchanneled edge of the muller.

According to my invention, the muller is used primarily for effectingthe mixture of pigments with oils, and in the service of the muller theunder surface of the unit so acts upon the pigment and oil as to effectan intimate admixture of the specified ingredients without anappreciable grinding action upon the pigment, the latter beingpre-ground in a suitable mill in accordance with the usual procedure inpreparing pigments for utilization in the paint art.

In a practical form, the muller is tubular with a cylindrical innersurface and a cylindrical outer surface. The muller is characterized byan under mixing surface the width of which is less than the thickness ofthe wall of the tubular unit. This reducton in the width of the mixingsurface is due to the presence on the inner cylindrical surface of abevel at the lower edge of the unit. The bevel extends from the innercylindrical surface to the under mixing surface, the angle ofinclination of said bevel affording ample space between the muller andthe subjacent platen for insuring an adequate flow of pigment and oil tothe under mixing surface.

The muller is constructed to produce an annular wall the thickness ofwhich is usually constant throughout the depth of the muller vxcept forthe lower edge portion, at which place the thickness of the wall isdecreased by the presence of the bevel provided on the lower innercylindrical surface.

In the service of my muller, the feed of the pigment and oil is in adirection from the interior of the unit toward the outer side of saidunit, and provision is made for excluding the re-entry of the pigmentand oil to the interior chamber, a sharp angle defining the juncture ofthe outer cylindrical surface with the plane surface of the subjacentplaten, with the distinct object of wholly precluding the re-entry ofthe mixed pigment and oil into contact with the under mixing surface ofthe muller. Briefly, the muller acts effciently to attain the mixturewhile the pigment and oil are incontact with the narrow under surface,and once the mixture passes beyond the outer limits of the muller, thenthe sharp angle at the outer surface acts to exclude the mixture fromre-entering below the muller for contact with the channeled mixingsurface.

Salient features of my hand operated muller are the bevel at the loweredge on the inner cylindrical surface, and a well defined sharp edge atthe lower edge on the outer surface, said sharp outer edge and the bevelon the inner surface bounding and limiting the mixing face at the loweredge, which mixing face is of a width appreciably less than thethickness of the wall of the muller. A further salient feature is thepresence in the relatively narrow mixing face of a succession ofchannels extending tangentially to the in ner surface, and in my mullerit is required, first, that said channels so direct the pigment and oilin a direction outwardly from the muller, or from the inside toward theoutside, and, second, that the channels open through and communicatewith the bevel 0n the inner cylindrical surface and terminate short ofthe sharp lower outer corner at the outside cylindrical surface.

To attain opea'tiveness, it is required that the muller be provided withthe bevel on the inner cylindrical surface at the lower corner thereofwhereby provision is made for the flow of materials from the chamber ofthe muller to the lower mixing surface. For directing the flow ofmaterials in a direction toward the outside of the muller, the channelsare positioned in the lower mixing surface tangentially to the innersurface, and to the end that no mixed materials may be permitted to flowbeneath, or re-enter below, the mixing face, the outer cylindricalsurface of the muller meets with the under mixing face at a sharp angle,the same being a right angle.

The interior of the tubular unit provides a chamber in which isdeposited the pigment and oil required to be mixed, and when said mulleris in use, the materials flow freely through the bevel and below themixing face. The mull-r is eficient to the extent that the mixture iscomplete once it passes to the outside of the muller, and in myinvention the construction excludes the re-entry of the mixed materialsbelow the lower edge of the unit for contact with the mixing face.

The details of the operation of the muller are as follows:

The muller is placed in position upon the grinding platen, with thelower or grinding surface of the muller in contact with the platen. Acharge of pigment and vehicle, either previously mixed together, or notmixed (the use of pigment and vehicle is here given for convenience, asrepresenting a well known application of the muller, but the applianceis equally suitable for grinding or mulling pharmaceutical mixtures orany other combination of materials whose intimate blending can beeffected by mulling action) is placed inside the muller, and if notpreviously mixed, the whole is stirred with a rod or other suitablestirring appliance until well blended. The muller is then given a rotarymotion or an elliptical or oscillatory movement with the hand, at thesame time applying downward pressure upon the muller. The mullerimmediately leaves in its wake a film of ground product, see Figure 3,which, with the continued rotations or oscillations of the muller,accumulates upon the grinding platen, and by reason of the sharp outerlower angle of the muller does not tend to reenter the muller. Theoperation is continued unil the desired amount of product is obtained,or until the muller is empty, at which point the muller may be rechargedwith additional material. It will be obvious that no ground material canappear upon the platen outside the muller without having passed betweenthe grinding surface of the muller and the surface of the platen, thusinsuring the production of a paste or paint completely and uniformlyground.

Although the term paste has been con veniently applied to the product toexemplify the use of the invention, it should be understood that theinvention is equally suitable for the grinding of pigments etc, carryingsuflicient vehicle to yield a relatively fluid mixture such as ordinaryoil paint.

On account of the relatively small area of the grinding surface of thistype of inuller, and hence the relatively high pressure per unit of areaobtainable with ease in practice as compared with the usual pestle typeof muller commonly used, the degree of comminution imparted to thepigments ground with the use of the appliance herein described r: ismuch greater in a given time and with less labor than is possible withthe existing types of mullers or niuller substitutes.

The action of the muller in actual use is illustrated diagrammaticallyin vertical cross section in Figure 3, A representing the charge ofunground material located within the central cavity of the muller; E,Figure 3, represents a portion of this material after having been groundby passing between the lower grinding surface of the muller and theupper surface of the grinding platen, O.

I claim:

1. A hand operated muller comprising a tubular unit the lower edge ofwhich constitutes a mixing face, the interior surface of said unit beingcylindrical and provided at the lower edge of said cylindrical surfacewith a bevel, said bevel being at an angle to the inner cylindricalsurface and to the plane of the mixing face.

2. A hand operated muller comprising a tubular unit having at the loweredge a plane mixing face, the inner surface of said unit beingcylindrical, said tubular unit being provided in said mixing face with asuccession of separate channels extending tangentially to the innersurface, and a bevel at the lower edge of the unit and on the innercylindrical surface thereof, said separate channels opening through saidbeveled inner surface of the unit.

3. A hand operated muller embodying a tubular unit provided on acylindrical inner surface with a bevel and on its under part with amixing surface, the width of said mixing surface being less than thethickness of the wall of said tubular unit.

4:. A hand operated muller embodying a tubular unit the under part ofwhich constitutes a mixing surface, feed channels in said mixingsurface, and a bevel on a cylindrical inner surface of said tubularunit, said channels having their origin at the bevel and extendingsubstantially to a line within an outer angle formed by the junction ofsaid mixing surface with the exterior surface of the unit.

5. A hand operated muller embodying a tubular unit the under surface ofwhich constitutes a mixing surface which joins at a sharp angle with theouter cylindrical surface of the muller, and feed channels in saidmixing surface, said feed channels terminating at their outer endswithin the sharp angle.

6. A hand operated muller embodying a tubular unit the under part ofwhich constitutes a mixing surface, a bevel on the inner cylindricalsurface of said unit, said bevel joining with said mixing surface, andfeed channels in said mixing surface, said feed channels extending fromsaid bevel substantially to a line defined by an angle at the junctureof the mixing surface with the outer surface of said tubular unit.

'4. A hand operated muller comprising a tubular unit having acylindrical inner surface and a cylindrical outer surface, a bevel onthe inner surface at the lower corner of the unit, said bevel extendingfrom the inner cylindrical surface to the lower edge of the unit andreducing the width of said lower edge to an appreciable extent less thanthe thickness of the wall of the unit, the outer cylindrical surface andthe under surface of said unit being at a right angle, and a successionof feed channels in the under surface, said feed channels being atangent to the inner cylindrical surface and said feed channelsextending from the inner bevel outwardly to a line defined by a rightangle formed by the juncture of the lower surface of the unit with theouter cylindrical surface of said unit.

LOUIS GEORGE COPES.

